Allelopathic Assessment of Extracts of Cashew Leaf and Stem Bark on Cajanus Cajan L. Millsp Seed

Anacardium occidentale commonly known as the cashew plant is a hardy drought-resistant tropical and subtropical tree. Cajanus cajan (pigeon pea) is one of the most important legumes grown in semi-arid tropical regions. The study examined the inhibitory effects of the leaves and stem bark extracts of cashew on the germination of pigeon pea seed. It was conducted in the laboratory of the Department of Plant Science and Biotechnology, Michael Okpara University of Agriculture, Umudike, Nigeria. The tests were carried out in sterilized Petri dishes filled with cotton wool. Various concentration of aqueous extracts of cashew leaves and stem bark, namely 30%, 50%, and 70%, were produced and given to the seeds, with distilled water serving as a control (0 percent). The aqueous extracts of both the cashew leaves and stem bark showed significant (p < 0.05) inhibitory effects on the germination percentage and germination rate of C. cajan as the concentrations increased. The cashew leaves extracts showed the maximum value at 70% (80.00%,) while the lowest value at control (96.66%). Also, the cashew stem bark extracts showed the maximum value at 70% (86.66%) while the lowest value at control (96.00%). These findings demonstrated that phytochemicals found in the tissues of A. occidentale had a significant phytotoxic effect on the germination of C. cajan seeds.